Patent GB-949052-A (GB)
Title: Sampling punch for continuous strip
IPC: G01N1/04
Filed: 1960-07-07
Abstract: 949,052. Punching. UNITED STATES STEEL CORPORATION. July 7, 1960 [July 15, 1959], No. 23821/60. Heading B3W. A punch for punching samples from moving strip S comprises punching mechanism 41, 42 on a carriage 1 adapted to be accelerated along the rectilinear path of the strip, and means 4 for operating the punching mechanism when the carriage-speed corresponds to that of the strip. The strip-path may be horizontal or (as shown) vertical and the carriage accelerated by gravity to the strip-speed. The strip is guided by rolls 5-7 through the carriage 1 which moves on guide posts 10 in a frame 2. A cable 13 connects the carriage to a hoist 3 including mechanism (not shown) for centralizing the cable. The hoist is driven by an electromotor 16. A freewheel 25 may couple, by means of a chain 27, the hoist 3 to the roll 6 to limit the speed of rotation of the hoist, as the carriage falls, to that of the roll 6. Alternatively, magnetic clutches (not shown) may couple the hoist to the motor 16, or the height to which the carriage is raised may be adjusted by varying the position of a limit-switch 18, Fig. 19, in the hoist drive, the switch-position being adjusted through a screw 31 and gearing 32 by a motor. The carriage 1 has two transverse posts 35, Fig. 8, on which slide punch and die holders 33, 34 supporting three punches 41, Fig. 10, and dies 42. A work clamping and stripping device 38 also slides on the posts and opposes a clamping device 40 on the die-holder 34. Operation of the holders 33, 34 and the stripper 38 is by cam units 4 fixed within the posts 10 and roller followers 44, 45, 48, Fig. 9, on the ends of the holders and stripper, those on the stripper being on pivotally mounted bell-crank levers 46, biased by springs 49. In the open position of the holders 33, 34, springs 37 hold them against stop-collars 37a on the rods 35. The cam units comprise cam-grooves 57, 58, Fig. 12, formed by rigid sections 61, 65 and movable sections 62, 66 arranged to increase the width of the cam-grooves during return movements of the carriage, so that the punches are not operated during these return movements. The movable sections 62, 66 are on links 68, 69 and in the closed setting rest on end-stops 73. Members 92, Fig. 17, on cross-heads 91 operated by double-acting pneumatic cylinders 88 pivot the sections 62, 66 into inoperative, open position against stops 75, the cylinders being controlled by the upper limit switch 18 on the frame and a lower limit switch 100 below the cam units, the switches being operated by contact with the carriage. Operation of the switch 100 by the carriage 1 during the downward stroke causes the retraction of the sections 62, 66. Operation of the upper switch 18 on return of the carriage interrupts the drive to the hoist and advances the sections 62, 66 which, when they engage the stop-pins 73, may operate contacts in the control circuit of motor 16 so as to release the carriage. Downward movement of the cross-head 91 is transmitted to the sections 62, 66 through spring-pressed rods 98, Fig. 17, and levers 94, 97 on pivots 95, The follower rollers 45 of the punch holder 33 are offset axially from those of the clamping and stripping device 38. Parts 60, 83 of the camgrooves 57, 58 cause the clamping and stripping devices to grip the moving strip, part 81 of groove 58 projecting the punches into the dies and withdrawing them while the stripper 38 remains in its forward position.